As the media world debates the impact of star witness Rachel Jeantel on the murder trial of George Zimmerman, it seems obvious the 19-year-old friend of shooting victim Trayvon Martin stumbled over one of the biggest issues few people talk about when opinionating on the case.

The supreme challenge of code-switching on a national stage.

Jeantel, revealed this week as the woman on the phone with Martin just before his fatal fight with Zimmerman, is one of the few people connected to the case who wasn’t swept up in the tsunami of media coverage last year, centered on the case of an unarmed black teen gunned down by neighborhood watch volunteer Zimmerman in Sanford, Fla.

One reason that happened, was because of a lie: She admitted telling Martin’s lawyer and family she was age 16, to keep her name out of the spotlight by claiming she was a minor. (when she spoke to ABC News through the family’s lawyer, she was just an anonymous voice on a speaker phone).

All that maneuver did, however, was delay the inevitable. And as her face and demeanor were revealed to the world over the past two days, Jeantel’s difficulty in carrying herself the way mainstream pundits and legal experts expected was painfully apparent.

She mumbled. She spoke in a jumble of words and phrases that other attorneys and even the mostly-white jury couldn’t understand. She had to admit dictating a letter she once claimed she wrote, which was sent to Martin’s mother describing what she heard during the night of his death

That admission came in the most painful way: Jeantel confessed she couldn’t read cursive writing.

(CNN anchor Wolf Blitzer may have called that admission "humiliating," but a friend who teaches as an adjunct at University of Tampa said many of her students can't read cursive, either.)

Such shortcomings may not have meant much among her friends or in Jeantel’s neighborhood, where she was raised in a Haitian family, learning Creole and Spanish before English. But Jeantel proved horribly bad at “code switching,” or communicating with people outside her friends, family and culture, where her style of talking, phrases and dress might not be understood or valued.

Small wonder legal experts and cable TV news commentators chewed into her performance, with two different talking heads on HLN’s After Dark show pronouncing her a “train wreck,” “churlish” and “acrimonious.”

Besides admitting she lied about skipping Martin’s funeral because she was in the hospital and admitting she may have softened her statements to prosecutors because she spoke in the presence of Martin’s mother, Sybrina Fulton, Jeantel also admitted her friend called Zimmerman a “creepy ass cracker” and the n-word while trying to figure out why he was following him.

Zimmerman’s attorney pounced, accusing Martin of bringing race into the confrontation first (how that happens through a comment made that Zimmerman couldn’t hear to someone who wasn’t at the scene, I’m not totally sure). But Jeantel responded that cracker was a term people used in her community, sparking another round of questions about whether “cracker” is even a racial slur.

But what so much of this really revealed was the gulf between middle-aged, middle class, mainstream codes of behavior and life among youth from poorer, non-white neighborhoods.

A national TV audience saw up close the gulf between a poor black girl and a dense and arcane legal system, where white lawyers speak in ten-dollar words based on the dead language of Latin. They couldn’t seemed further apart if Jeantel was born on the moon.

This is a question that’s hovered over the Trayvon Martin shooting since the story burst onto the national stage more than a year ago.

As each side on this murder trial tries to prove the other person had tendencies toward prejudice and violence which may have sparked the fight, how will jurors judge the difference between edgy culture and outright dysfunction?

On Thursday, The Smoking Gun subjected Jeantel to similar treatment, detailing how her Twitter account was scrubbed of messages referring “to drinking, smoking, and getting high. She also made references to Martin’s death, referred to acquaintances as ‘bitch’ and ‘nigga,’ and wrote about having ‘jackass lawyers on my ass.’” She also had a picture tagged “court nails,” showing off a new manicure.

So is this stuff the code of youths growing up in a tough neighborhood, or the language of violence-prone “thugs” who may have deserved law enforcement attention?

Those questions rose weeks ago, when Zimmerman’s lawyers astutely posted more photos from Martin’s phone and social media accounts on their website, creating more stories on the teen’s passion of photos with guns and marijuana plants, flipping off the camera.

If Jeantel had more experience navigating these two worlds – the culture she lives in and straight-laced world of lawyers, jurors and TV commentators – she might have avoided some of the worst embarrassments of her testimony, including long stretches where everyone in the court said they could not understand her.

Predictably, social media has piled up with smug comments from people on her appearance and demeanor, including one MSN commenter who wrote “If you want to be taken seriously, you have to behave in such a way that people WILL take you seriously.”

But which culture decides what constitutes such behavior? And if you don’t know how to act that way for that culture, is it fair that you’re not taken seriously in a court of law?

Scary to think that, in the end, the verdict on whether Zimmerman murdered Martin may come down to how well the dead teen’s friends and family can speak to mainstream America.